U.S. accident investigators are set to begin probing the "black box" from the doomed freighter El Faro, hoping data will show what happened aboard the ship in the hours before it sank last year in the Atlantic with 33 people on board. There were no survivors.

Search teams returned Friday to a U.S. naval base in Florida with the data recorders, which were recovered from a depth of 4,500 meters 10 months after the 240-meter ship sank in a hurricane east of the Bahamas.

Investigators say the recorder is designed to record and store 12 hours of communications from the bridge, and is also expected to contain valuable navigational data. But a spokesman for the National Transportation Safety Board said it could take weeks to complete a the probe.

The U.S.-flagged ship was carrying cargo from Jacksonville, Florida, to San Juan, Puerto Rico, when it got caught October 1 in Hurricane Joaquin -- a powerful category 4 storm with 12-meter waves and winds as high as 215 kph.

The ship sent a satellite distress message shortly before land-based authorities lost contact with the crew of 28 Americans and five Poles.

In the days after the disaster, authorities speculated the ship may have lost power, leaving it defenseless and unable to navigate near the eye of the hurricane.